What you need to know about checking hard drive health

A hard drive fails without warning, but it usually sends signals first. You can read those signals using free tools built into Windows and macOS, or third-party programs that decode the data your drive reports about itself. The most useful signal is S.M.A.R.T. data — a standard that all modern drives use to log their own temperature, error rates, and wear patterns. Checking this data takes five to ten minutes and tells you whether your drive is healthy, degrading, or near failure.

You do not need technical knowledge to do this. The tools show you a simple status — green means healthy, yellow means watch it, red means back up now. The hard part is not reading the data; it is deciding what to do with it. A drive showing yellow warnings might work for another year or fail next week. This guide shows you how to check, what the results mean, and when to replace your drive.

Key Takeaways

  • Windows includes a built-in tool called Check Disk that scans for errors, and third-party programs like CrystalDiskInfo read S.M.A.R.T. data to predict failure.
  • S.M.A.R.T. status shows temperature, reallocated sectors, and spin-up time — yellow warnings mean the drive is degrading and you should back up soon.
  • Red status or repeated yellow warnings mean replace the drive within days or weeks, not months.
  • External drives and SSDs use the same S.M.A.R.T. system, so the same tools work for all storage devices.

Using Windows Check Disk to scan for errors

Windows has a built-in tool called Check Disk that scans your drive for bad sectors and file system errors. Open File Explorer, right-click the drive you want to check, select Properties, then click the Tools tab. You will see a button labeled "Check." Click it and Windows will offer to scan the drive the next time you restart your computer.

Check Disk runs before Windows loads and reports what it found. If it finds and fixes errors, your drive is still working but has damage. If it finds nothing, that does not mean your drive is healthy — it only means the file system is intact. Check Disk does not read S.M.A.R.T. data, so it misses early warning signs that a drive is about to fail. Use it as a first step, but follow it with a S.M.A.R.T. reader for a complete picture.

The scan takes longer on larger drives — a 1 TB drive might take 30 minutes to an hour. You can schedule it for a time when you do not need your computer. If Check Disk finds errors repeatedly, that is a sign the drive is failing and you should back up your files immediately.

Reading S.M.A.R.T. data with CrystalDiskInfo or similar tools

CrystalDiskInfo is a free program that reads S.M.A.R.T. data directly from your drive and displays it in plain language. Download it from the official CrystalDiskInfo website, install it, and run it. The program shows your drive's status as a large colored circle — green means good, yellow means caution, red means critical. Below that you see individual metrics: temperature, reallocated sectors, uncorrectable errors, and power-on hours.

Other tools that do the same thing include Hard Disk Sentinel (paid, more detailed), Seagate SeaTools (free, works on any brand), and Speccy (free, shows multiple system details). All of them read the same S.M.A.R.T. data, so pick whichever interface you find clearest. CrystalDiskInfo is the most straightforward for beginners.

Run the tool once a month or whenever you notice your computer slowing down. If the status changes from green to yellow, note the date and check again in two weeks. If it stays yellow or turns red, back up your files to an external drive or cloud storage before doing anything else. A yellow drive can fail suddenly, so do not wait.

What S.M.A.R.T. warnings actually mean

S.M.A.R.T. tracks several measurements. Temperature above 50°C (122°F) is warm; above 60°C is hot and shortens drive life. Reallocated sectors means the drive found bad spots and moved your data to healthy areas — one or two is normal wear, but double-digit numbers mean the drive is failing. Uncorrectable errors means the drive tried to read data and could not fix it; even one of these is a red flag. Power-on hours

A yellow status usually means one or two metrics are in the warning range but not critical. This does not mean your drive will fail tomorrow. It means the drive is degrading and you should plan to replace it within weeks or months. Back up your important files now, but you can keep using the drive while you shop for a replacement.

A red status or a metric in the critical range means replace the drive immediately. Do not wait for it to fail completely. Do not run heavy tasks like video editing or large file transfers. Back up what you need and order a replacement today.

Checking external drives and SSDs

External hard drives and solid-state drives (SSDs) report S.M.A.R.T. data the same way internal drives do. Plug in the external drive, open CrystalDiskInfo or another S.M.A.R.T. reader, and it will show the external drive in the list. Select it and read the status the same way you would for an internal drive.

SSDs do not have spinning platters or moving heads, so they do not report temperature or reallocated sectors the same way. Instead, they report wear leveling — how evenly the drive has distributed writes across its memory cells. An SSD showing yellow wear leveling warnings still has years of life left, but it is aging faster than normal. Red warnings on an SSD mean the same thing as on a hard drive: replace it soon.

External drives are harder to replace than internal ones, so check them more often. If an external drive shows yellow warnings, move its contents to another drive and retire it. External drives are convenient, but they are not worth losing data over.

When to replace your drive versus when to keep watching

A drive showing green status can fail without warning, but it is statistically safe to keep using. Check it every few months. A drive showing yellow status is degrading and you should have a replacement plan — order a new drive and set a date to swap it out within the next month. A drive showing red status or critical errors should be replaced within days.

If your drive is under warranty, contact the manufacturer with your S.M.A.R.T. data. Most drive makers will replace a drive showing critical S.M.A.R.T. errors even if it still works. If your drive is out of warranty, you have two choices: replace it now while it still works, or back up everything and wait for it to fail. Waiting is cheaper but riskier — a failing drive can corrupt files as it dies, and you might lose data even if you have a backup.

For a drive that is old but showing green status, check it twice a year. Drives older than five years can fail suddenly even with good S.M.A.R.T. data. If your drive is over five years old and you cannot afford to lose the data on it, replace it proactively. If it is a secondary drive with files you do not need, you can keep using it until it fails.

Frequently Asked Questions

Can a drive fail even if S.M.A.R.T. shows green?

Yes. S.M.A.R.T. predicts failure based on wear patterns, but a sudden physical failure — a head crash or motor failure — can happen without warning. Green status means the drive is healthy now, not that it will never fail. Check your drive every few months and keep backups of important files regardless of what S.M.A.R.T. says.

What is the difference between Check Disk and S.M.A.R.T. readers?

Check Disk scans the file system for errors and fixes them. S.M.A.R.T. readers show the drive's internal health metrics. Check Disk finds problems that already happened; S.M.A.R.T. predicts problems that are about to happen. Use both — Check Disk first, then a S.M.A.R.T. reader for the full picture.

How often should I check my drive's health?

Once a month is enough for most people. If your drive is over five years old, check it every two weeks. If it shows yellow warnings, check it weekly to see if it is getting worse. If it shows red warnings, do not wait — back up and replace it immediately.

Does checking S.M.A.R.T. data damage my drive?

No. Reading S.M.A.R.T. data does not write anything to the drive or cause any wear. You can check it as often as you want without risk. The only thing that wears a drive is normal use — reading and writing files.

What should I do with a drive that shows yellow warnings?

Back up your important files to another drive or cloud storage within the next week. Order a replacement drive and plan to swap it out within the next month. Keep using the old drive for now, but do not store anything on it that you cannot afford to lose. If the status turns red, replace it immediately.